new length detection for non-string in UNION (BUG#4067)

mysql-test/r/subselect.result

@@ -1075,24 +1075,24 @@ CREATE TABLE t1 SELECT * FROM (SELECT 1 as a,(SELECT 1)) a;
 SHOW CREATE TABLE t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` bigint(1) NOT NULL default '0',
-  `(SELECT 1)` bigint(1) NOT NULL default '0'
+  `a` bigint(20) NOT NULL default '0',
+  `(SELECT 1)` bigint(20) NOT NULL default '0'
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 CREATE TABLE t1 SELECT * FROM (SELECT 1 as a,(SELECT a)) a;
 SHOW CREATE TABLE t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` bigint(1) NOT NULL default '0',
-  `(SELECT a)` bigint(1) NOT NULL default '0'
+  `a` bigint(20) NOT NULL default '0',
+  `(SELECT a)` bigint(20) NOT NULL default '0'
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 CREATE TABLE t1 SELECT * FROM (SELECT 1 as a,(SELECT a+0)) a;
 SHOW CREATE TABLE t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` bigint(1) NOT NULL default '0',
-  `(SELECT a+0)` bigint(17) NOT NULL default '0'
+  `a` bigint(20) NOT NULL default '0',
+  `(SELECT a+0)` bigint(20) NOT NULL default '0'
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 CREATE TABLE t1 SELECT (SELECT 1 as a UNION SELECT 1+1 limit 1,1) as a;
@@ -1102,7 +1102,7 @@ a
 SHOW CREATE TABLE t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` bigint(17) NOT NULL default '0'
+  `a` bigint(20) NOT NULL default '0'
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 (a int);

mysql-test/r/union.result

@@ -546,7 +546,7 @@ aa
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` char(2) NOT NULL default ''
+  `a` char(20) NOT NULL default ''
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 SELECT 12 as a UNION select 12.2 as a;
@@ -557,7 +557,7 @@ a
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `a` double(4,1) NOT NULL default '0.0'
+  `a` double(53,1) NOT NULL default '0.0'
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t2 (it1 tinyint, it2 tinyint not null, i int not null, ib bigint, f float, d double, y year, da date, dt datetime, sc char(10), sv varchar(10), b blob, tx text);
@@ -647,7 +647,7 @@ f
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `f` binary(12) default NULL
+  `f` binary(24) default NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 SELECT y from t2 UNION select da from t2;
@@ -795,7 +795,7 @@ select * from t1;
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `1` bigint(1) NOT NULL default '0'
+  `1` bigint(20) NOT NULL default '0'
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 select _latin1"test" union select _latin2"testt" ;
@@ -953,3 +953,10 @@ CREATE TABLE t2 (i int(11) default NULL,c char(1) default NULL,KEY i (i));
 explain (select * from t1) union (select * from t2) order by not_existing_column;
 ERROR 42S22: Unknown column 'not_existing_column' in 'order clause'
 drop table t1, t2;
+CREATE TABLE t1 (uid int(1));
+INSERT INTO t1 SELECT 150;
+SELECT 'a' UNION SELECT uid FROM t1;
+a
+a
+150
+drop table t1;

mysql-test/t/union.test

@@ -527,3 +527,11 @@ CREATE TABLE t2 (i int(11) default NULL,c char(1) default NULL,KEY i (i));
 --error 1054
 explain (select * from t1) union (select * from t2) order by not_existing_column;
 drop table t1, t2;
+
+#
+# length detecting
+#
+CREATE TABLE t1 (uid int(1));
+INSERT INTO t1 SELECT 150;
+SELECT 'a' UNION SELECT uid FROM t1;
+drop table t1;

sql/item.cc

@@ -2419,6 +2419,7 @@ Item_type_holder::Item_type_holder(THD *thd, Item *item)
     field_example= ((Item_field*) item)->field;
   else
     field_example= 0;
+  max_length= real_length(item);
   collation.set(item->collation);
 }
 
@@ -2438,6 +2439,7 @@ static Item_result type_convertor[4][4]=
 
 bool Item_type_holder::join_types(THD *thd, Item *item)
 {
+  uint32 new_length= real_length(item);
   bool change_field= 0, skip_store_field= 0;
   Item_result new_type= type_convertor[item_type][item->result_type()];
 
@@ -2463,7 +2465,7 @@ bool Item_type_holder::join_types(THD *thd, Item *item)
   // size/type should be changed
   if (change_field ||
       (new_type != item_type) ||
-      (max_length < item->max_length) ||
+      (max_length < new_length) ||
       ((new_type == INT_RESULT) &&
        (decimals < item->decimals)) ||
       (!maybe_null && item->maybe_null) ||
@@ -2472,7 +2474,7 @@ bool Item_type_holder::join_types(THD *thd, Item *item)
   {
     // new field has some parameters worse then current
     skip_store_field|= (change_field &&
-			(max_length > item->max_length) ||
+			(max_length > new_length) ||
 			((new_type == INT_RESULT) &&
 			 (decimals > item->decimals)) ||
 			(maybe_null && !item->maybe_null) ||
@@ -2501,7 +2503,7 @@ bool Item_type_holder::join_types(THD *thd, Item *item)
       return 1;
     }
 
-    max_length= max(max_length, item->max_length);
+    max_length= max(max_length, new_length);
     decimals= max(decimals, item->decimals);
     maybe_null|= item->maybe_null;
     item_type= new_type;
@@ -2510,6 +2512,70 @@ bool Item_type_holder::join_types(THD *thd, Item *item)
   return 0;
 }
 
+uint32 Item_type_holder::real_length(Item *item)
+{
+  if (item->result_type() == STRING_RESULT)
+    return item->max_length;
+  if (item->type() == Item::FIELD_ITEM)
+  {
+    switch (((Item_field *)item)->field_type())
+    {
+      case MYSQL_TYPE_TINY:
+        return 4;
+      case MYSQL_TYPE_SHORT:
+        return 6;
+      case MYSQL_TYPE_LONG:
+        return 11;
+      case MYSQL_TYPE_FLOAT:
+        return 24;
+      case MYSQL_TYPE_DOUBLE:
+        return 53;
+      case MYSQL_TYPE_NULL:
+        return 4;
+      case MYSQL_TYPE_LONGLONG:
+        return 20;
+      case MYSQL_TYPE_INT24:
+        return 8;
+      case MYSQL_TYPE_TINY_BLOB:
+        return 256;
+      case MYSQL_TYPE_MEDIUM_BLOB:
+        return 65535;
+      case MYSQL_TYPE_LONG_BLOB:
+        return (uint32)4294967295;
+      case MYSQL_TYPE_BLOB:
+        return 16777215;
+      case MYSQL_TYPE_SET:
+      case MYSQL_TYPE_ENUM:
+      case MYSQL_TYPE_NEWDATE:
+      case MYSQL_TYPE_YEAR:
+      case MYSQL_TYPE_DATETIME:
+      case MYSQL_TYPE_TIME:
+      case MYSQL_TYPE_DATE:
+      case MYSQL_TYPE_TIMESTAMP:
+      case MYSQL_TYPE_DECIMAL:
+      case MYSQL_TYPE_VAR_STRING:
+      case MYSQL_TYPE_STRING:
+      case MYSQL_TYPE_GEOMETRY:
+        return item->max_length;
+      default:
+        DBUG_ASSERT(0); // we should never go there
+        return 0;
+    }
+  }
+  switch (item->result_type())
+  {
+  case STRING_RESULT:
+    return item->max_length;
+  case REAL_RESULT:
+    return 53;
+  case INT_RESULT:
+    return 20;
+  case ROW_RESULT:
+  default:
+    DBUG_ASSERT(0); // we should never go there
+    return 0;
+  }
+}
 
 double Item_type_holder::val()
 {

sql/item.h

@@ -1199,6 +1199,7 @@ public:
   String *val_str(String*);
   bool join_types(THD *thd, Item *);
   Field *example() { return field_example; }
+  static uint32 real_length(Item *item);
   void cleanup()
   {
     DBUG_ENTER("Item_type_holder::cleanup");